Apparatus for positioning slit chain bushes

ABSTRACT

A strip of material is punched at intervals, slit into lengths through the apertures, and formed into cylindrical apertured bushes. The bushes are mounted on a conveyor having pins with spring-loaded catches, are mechanically rotated until the catches engage the apertures to locate the seams in face-to-face relationship, and are press fitted to backing plates. This enables manufacture of a chain wherein all the link bushes have optimum bearing characteristics.

Uite States Patent lnventor Peter T. Schafer Eschwege, Germany Appl No.800,175

Filed Feb. 18, I969 Patented June 8, 1971 Assignee Massey-Ferguson GmbH.

Kassel, Germany Priority Feb. 28, 1968 Germany M6l,529

APPARATUS FOR POSITIONING SLIT CHAIN BUSHES 4 Claims, 7 Drawing Figs.

US. Cl 59/4,

59/8, 59/35, 74/250 Int. Cl B21] 9/02 Field of Search 59/1, 468,

[ References Cited UNITED STATES PATENTS 2,105,048 1/1938 Lauenstein59/8 3,426,522 2/1969 Onulak 59/8 FOREIGN PATENTS 673,452 11/1963 Canada59/4 Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P.Crosby AtIorney-Gerhardt, Greenlee & Farris ABSTRACT: A strip ofmaterial is punched at intervals, slit into lengths through theapertures, and formed into cylindrical apenured bushes. The bushes aremounted on a conveyor having pins with spring-loaded catches, aremechanically rotated until the catches engage the apertures to locatethe seams in face-to-face relationship, and are press fitted to backingplates. This enables manufacture of a chain wherein all the link busheshave optimum bearing characteristics.

PATENTED JUN 8131: 3533.153

' SHEET 2 OF 4 A Home ys AIIAIRATUS FOR POSITIONING SLIT CHAIN BUSIHESThis invention relates to roller chains.

Hitherto in the manufacture of roller chain links comprising twoidentical bushes press fitted to a backing or mounting plate inspaced-apart relationship, the bushes have been manufactured from acontinuous strip of metal without waste of the material. The metal striphas been guided into the bushforming machine by a reel and grippingtongs, and straightened and cut into short lengths as required. Theseshort lengths have thereafter been pressed into the basic bush shapearound a former and then pulled through a die so as to calibrate boththe inside and the outside measurements of the bush. In this mannercylindrical bushes have been formed having a narrow slit or seam wherethe two edges ofthe flat metal have been abutted.

Links for use in roller chains, when utilizing such a bush, are known tohave a short working life which, to a large extent. is due to the factthat the seams are not located in a preferred position before the bushesare press fitted to the backing plate. Thus several successive links ofthe chain may include bushes which have seams located in a zone of highstress and uneven wear of the chain occurs, especially in highlystressed chains such as drum chains.

An object of the present invention is to provide a method of andapparatus for manufacturing roller chain bushes as a result of which thebushes have apertures through which the seams pass.

A further object of the present invention is to provide apparatus forassembling a roller chain link, which enables precise alignment of theseams of bushes which have apertures through which the seams pass.

According to the present invention, there is provided apparatus formanufacturing bushes for a roller chain link from a strip of material,said apparatus including a strip-shearing mechanism and a bush-formingdevice in which cut lengths of the strip are formed into cylindricalbushes, including a punching device for punching apertures in the stripat such intervals that the shearing of the strip is effected through theapertures.

Further, according to the present invention there is provided apparatusfor assembling a roller chain link having a backing plate and first andsecond seamed cylindrical bushes with circular apertures diametricallydisposed through the seams thereof, said apparatus including a base, atable rotatably mounted on the base, and pairs of first and secondspaced-apart locating pins upstanding from said table and on which thebushes are sliding fits, and the pins ofeach pair have face-to-facealigned spring-loaded catches for engagement with the apertures in thebushes, and a brake is mounted on the base and is adapted, when in use,to bear against the outer surfaces of the bushes to rotate same relativeto the backing plate until the catches engage with the apertures.

Still further, according to the present invention there is provided amethod of manufacturing roller chain links each of which includes abacking plate and first and second cylindrical seamed bushes, saidmethod including the steps of provided a circular aperture in each bushdiametrically through the seam thereof, mounting the backing plate on atemplate, positioning the bushes in spaced-apart relationship on thetemplate for press fitting to the backing plate, mechanically rotatingeach bush until the apertures therein are substantially in face-tofacealignment with each other, and thereafter press fitting each bush to thebacking plate.

Embodiments of the present invention will now be described, by way ofexample, with reference to the accompanying drawings, in which:

FIG. I is a schematic diagram of apparatus for manufacturing rollerchain bushes according to the present invention;

FIG. la is a plan view of the workpiece strip shown in FIG.

FIG. 2 is a view, to an enlarged scale, of the hole-punching apparatusshown in FIG. 1;

FIG. 3 is a disc for aligning the seams of the bushes;

FIG. 4 is a detail of FIG. 3 shown to an enlarged scale;

FIG. 5 is a sectional view taken on the line AB in FIG. 3, shown to anenlarged scale, ofthe bush alignment pin arrangement;

FIG. 6 is a modified arrangement of bush alignment pins; and

FIG. 7 is a part ofa roller chain including a bush manufacturedaccording to the present invention.

As is shown in FIG. I, in apparatus for manufacturing bushes for rollerchains, the material from which the bushes are formed is wound in a coil10 from which a strip of material is fed through a series ofspaced-apart rollers 11 so as to straighten the strip of material whichthereafter successively undergoes the processes of aperture punching,shearing, and bush forming or winding.

In the aperture-punching process, the strip of material is formed overan anvil l2 and a punching tool I3, which is reciprocally slideable in aguideway I4, is automatically moved so that the tool 13 punches anaperture in the strip of material and discharges the punched materialthrough a passage IS in the anvil 12. A clamp I2A prevents movementofthe strip of material during the punching operation.

The punching tool I3, as is shown in FIG. 2, is pivotally mountedadjacent one end of a lever 16, which is pivotally mounted intermediateits ends on a pin 19 on the body of the bush-forming apparatus. The endofthe lever 16 remote from that connected to the tool 13 carries aroller 17 which engages a sliding carriage l8, movement of which isconfined to reciprocation in the direction of the arrows B in FIG. 2.When the carriage 18 moves to the left, a shoulder 18A on the carriage18 engages the roller 17 and causes the lever 16 to pivot about the pin19 thereby moving the tool 13 so as to punch an aperture in the strip ofmaterial.

After the aperture-punching process is completed, the sliding carriage18 is moved to the right in FIG. 2 and the punching tool 13 is retractedto the inoperative position shown in FIG. 2, by a return spring 20A.

On completion of the aperture-punching process a pair of gripping tongs20 Clasps the strip of material and moves it a predetermined distancetowards a shearing mechanism 21. Thereafter the tongs 20 are returned totheir initial position. The predetermined distance moved by the tongs 20is equal to the length of the strip of material required to form onechain bush and to the spacing between the apertures punched in thestrip.

Furthermore, the distance between the shearing edge of the mechanism 21and the central axis of the punching tool 13 is a multiple of the lengthof material required to form one chain bush. In this way shearing of thestrip takes place diametrically through the punched apertures and eachlength of strip from which a bush is to be formed has semicircularnotches in its ends.

On completion of the shearing process the piece of material is formedinto a cylindrical bush by a winding device 25, which includes first andsecond jaws 26, 26A each of which has a cylindrical concave surface, anda cylindrical forming bar 27 round which the cylindrical bush is formed.The dimensions of the device 25 are such that the inner and outersurfaces of the bush are accurately calibrated, and the two portions ofthe punched apertures at the ends of the flat piece of material areabutted so as to form an aperture of approximately circular crosssection diametrically positioned on the seam of the bush.

In operation of the apparatus, movement of the sliding carriage 18, thetongs 20, the punching tool 13 and the shearing mechanism 21 aresynchronized so that. punching and shearing occur simultaneously andafter forward movement of the tongs 20 has ceased.

Bushes produced by the aforementioned apparatus may be fitted in pairsto the backing plates of chain links with the seams of each pair, inexact face-to-face alignment, by the apparatus shown in FIGS. 3, 4 and5.

The apparatus includes a revolving table 30 around the periphery ofwhich there is a series of upstanding spring' loaded pins 31 each ofwhich has a spring-loaded catch or nose 31A projecting radially from thepin 3i at an initially predetermined spacing from the surface of thetable 30. The pins 31 are equally spaced-apart so that a backing plate32 may be fitted over a pair of the pins 31 so as to bear on the surfaceof the table 30, with the pins 32 projecting through the apertures oftheplate 32.

The pairs of pins 31 are arranged so that the respective catches 31A arein precise face-to-face alignment and when the catches 31A engage theapertures of the bushes the seams of the bushes are in preciseface-to-face alignment.

In this way it is possible to ensure that the bush seams are in precisealignment and are situated in the zone of lowest stress in the completedchain.

Bushes 33 having circular apertures 34 through their seams arethereafter positioned over the pins 31 and each bush 33 is rotated aboutits respective pin 31 so that the spring-loaded catch 31A engages theapertures 34 thus to locate the bushes 33 relative to one another. Thisprocess is achieved by a spring-loaded frictional brake 35 shown in H05.3 and 4. The brake 35 has a lever 37 of which the surface 36 has afriction lining, and the lever 37 is urged by a spring 37A away from astationary housing 38 and into contact with the bushes 33 which aremoved relative to the lever 37 by rotation of the table 30.

Final location of the bushes 33 relative to the respective backing plate32 is achieved by a press-fitting operation during which the catch 31Aremains engaged in the aperture 34 and the entire pin 31 moves relativeto the table 30 due to the lower edge of the bush 33 bearing on ashoulder 31B of the pin 31.

A modified arrangement of locating pin 31 is shown in H6. 6 in which thepin is hollow and the catch is in the form ofa V- shaped spring 31B theapex of which projects radially through an aperture 31C in the wallofthe pin.

Part of a complete roller chain including a link having bushesmanufactured as above is illustrated in FIG. 7. The bushes 33, theapertures 34 and the backing plates 32 are each shown, and it will beevident that the apertures 34 are set in line. Sleeves 40 are fittedexternally to the bushes 33 for engagement with the sprockets of asprocket wheel, the links are interconnected by pins 41 which passthrough and are a bearing fit in the bushes 33. The pins 41 are rivettedor otherwise connected to plates 42.

In a modified roller chain the pins 41 are replaced by cylindrical tubessecured to the plates 42.

In a modification of the apparatus for aligning the seams of the bushesthe table 30 is in the form ofan endless conveyor so that the processesof mounting the backing plate, mounting the bushes thereon, rotating thebushes relative to the pin, and press fitting the bushes to the backingplate are carried out with a linear motion of the backing plate.

lclaim:

1. Apparatus for assembling a roller chain link having a backing plateand first and second seamed cylindrical bushes with circular aperturesdiametrically disposed through the seams thereof, said apparatusincluding a base, a table rotatably mounted on the base, pairs of firstand second spaced-apart locating pins upstanding from said table and onwhich the bushes are sliding fits, the pins of each pair havingface-toface aligned spring-loaded catches for engagement with theapertures in the bushes, and a brake mounted on the base for bearingagainst the outer surfaces of the bushes to rotate the bushes relativeto the backing plate until the catches engage with the apertures.

2. Apparatus as claimed in claim 1, wherein the pins are resilientlymounted on the table.

3. Apparatus as claimed in claim 1, wherein the brake is resilientlymounted on the base.

4. A method of manufacturing roller chain links each of which includes abacking plate and first and second cylindrical seamed bushes, saidmethod including the steps of providing a circular aperture in each bushdiametrically through the seam thereof, mounting the backing plate on atemplate, positioning the bushes in spaced-apart relationship on thetemplate for press fitting to the backing plate, mechanically rotatingeach bush until the apertures therein are substantially in face-tofacealignment with each other, and thereafter press fitting each bush to thebraking plate.

1. Apparatus for assembling a roller chain link having a backing plate and first and second seamed cylindrical bushes with circular apertures diametrically disposed through the seams thereof, said apparatus including a base, a table rotatably mounted on the base, pairs of first and second spaced-apart locating pins upstanding from said table and on which the bushes are sliding fits, the pins of each pair having face-to-face aligned spring-loaded catches for engagement with the apertures in the bushes, and a brake mounted on the base for bearing against the outer surfaces of the bushes to rotate the bushes relative to the backing plate until the catches engage with the apertures.
 2. Apparatus as claimed in claim 1, wherein the pins are resiliently mounted on the table.
 3. Apparatus as claimed in claim 1, wherein the brake is resiliently mounted on the base.
 4. A method of manufacturing roller chain links each of which includes a backing plate and first and second cylindrical seamed bushes, said method including the steps of providing a circular aperture in each bush diametrically through the seam thereof, mounting the backing plate on a template, positioning the bushes in spaced-apart relationship on the template for press fitting to the backing plate, mechanically rotating each bush until the apertures therein are substantially in face-to-face alignment with each other, and thereafter press fitting each bush to the braking plate. 